What Type of Literature is This?

“The first qualification for judging any piece of workmanship from a corkscrew to a cathedral is to know what it is - what it was intended to do and how it is meant to be used. After that has been discovered the temperance reformer may decide that the corkscrew was made for a bad purpose, and the communist may think the same about the cathedral. But such questions come later. The first thing is to understand the object before you: as long as you think the corkscrew was meant for opening tins or the cathedral for entertaining tourists you can say nothing to the purpose about them. The first thing the reader needs to know about Paradise Lost is what Milton meant it to be.” ....